Oesophageal electrocardiography in healthy horses
Article first published online: 14 DEC 2011
© 2011 EVJ Ltd
Equine Veterinary Journal
Volume 44, Issue 6, pages 640–645, November 2012
How to Cite
Verheyen, T., Decloedt, A., De Clercq, D., Sys, S. and Van Loon, G. (2012), Oesophageal electrocardiography in healthy horses. Equine Veterinary Journal, 44: 640–645. doi: 10.1111/j.2042-3306.2011.00526.x
- Issue published online: 29 OCT 2012
- Article first published online: 14 DEC 2011
- Received: 01.07.11; Accepted: 08.10.11
Reasons for performing study: In human medicine, oesophageal electrocardiography (ECG) is a well-established technique that magnifies P waves with respect to the QRS complex.
Objectives: To investigate the feasibility of oesophageal ECG recording in horses and its ability to produce larger P waves compared with base-apex and unipolar recordings.
Methods: Bipolar and unipolar ECG were performed using oesophageal and surface electrodes. Oesophageal ECG was obtained from 6 different recording configurations at different oesophageal depths. Amplitudes of P, Q, R, S and T waves were measured from 3 different cardiac cycles for each recording configuration and depth.
Results: Oesophageal ECG was feasible in all horses. For all oesophageal recording configurations, significantly larger P waves were recorded from a depth that equalled ‘height of the withers + 10 cm’ (HW+10) than from any other depth. P/QRSmagn, the ratio between the P wave and QRS complex magnitudes, was largest for intraoesophageal recordings with an interelectrode distance of 10 cm, at HW+10, where it was significantly larger than base-apex and unipolar recordings. Base-apex recording resulted in significantly smaller P waves than all other recording configurations and significantly smaller P/QRSmagn ratios than all other recording configurations except one combined oesophageal-surface recording (E/Slow).
Conclusions: Oesophageal ECG recording is feasible in horses and effective in magnifying P wave amplitude.
Potential relevance: The procedure is promising for diagnosis of supraventricular tachydysrhythmias and might be used in electrophysiological studies and for cardiac pacing.